#define _CRT_SECURE_NO_WARNINGS 1


#include <stdio.h>
#include<math.h>

int main() {
    double cur = 0;
    double next = 0;
    double sum = 0;
    int num = 0;
    while (scanf("%lf%d", &cur, &num) != EOF)
    {
        sum = 0;
        for (int i = 0; i < num; i++) {
            sum += cur;
            next = pow(cur, 0.5);
            cur = next;
        }
        printf("%.2lf\n", sum);
    }
    return 0;
}